Computer graphics term for "non-photorealistic".
Many 3D renderers render photorealistic images, that is, pictures look "real". It's "easy" to do.
However, there are techniques in 3D rendering that allow rendition of non-photorealistic pictures - in other words, pictures that look as if those had been drawn or painted by humans.
These rendering techniques are fast enough for real-time rendering now, and have been somewhat used in computer games. Some new "cartoon"-style games (Jet Set Radio, for example) use cel shading NPR renderers that turn 3D models into 2D characters in real time. There's even a version of Quake out there (NPRQuake) that shows sketch-like or blueprint-like pictures.
See also: cel shading